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0a6d1fa0d2
32-bit userspace will now always see the same vDSO, which is exactly what used to be the int80 vDSO. Subsequent patches will clean it up and make it support SYSENTER and SYSCALL using alternatives. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/e7e6b3526fa442502e6125fe69486aab50813c32.1444091584.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
95 lines
1.9 KiB
C
95 lines
1.9 KiB
C
/*
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* (C) Copyright 2002 Linus Torvalds
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* Portions based on the vdso-randomization code from exec-shield:
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* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
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*
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* This file contains the needed initializations to support sysenter.
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*/
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#include <linux/init.h>
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#include <linux/smp.h>
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#include <linux/kernel.h>
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#include <linux/mm_types.h>
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#include <asm/cpufeature.h>
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#include <asm/processor.h>
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#include <asm/vdso.h>
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#ifdef CONFIG_COMPAT_VDSO
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#define VDSO_DEFAULT 0
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#else
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#define VDSO_DEFAULT 1
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#endif
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/*
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* Should the kernel map a VDSO page into processes and pass its
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* address down to glibc upon exec()?
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*/
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unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
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static int __init vdso32_setup(char *s)
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{
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vdso32_enabled = simple_strtoul(s, NULL, 0);
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if (vdso32_enabled > 1)
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pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n");
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return 1;
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}
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/*
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* For consistency, the argument vdso32=[012] affects the 32-bit vDSO
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* behavior on both 64-bit and 32-bit kernels.
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* On 32-bit kernels, vdso=[012] means the same thing.
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*/
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__setup("vdso32=", vdso32_setup);
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#ifdef CONFIG_X86_32
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__setup_param("vdso=", vdso_setup, vdso32_setup, 0);
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#endif
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int __init sysenter_setup(void)
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{
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init_vdso_image(&vdso_image_32);
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return 0;
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}
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#ifdef CONFIG_X86_64
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subsys_initcall(sysenter_setup);
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#ifdef CONFIG_SYSCTL
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/* Register vsyscall32 into the ABI table */
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#include <linux/sysctl.h>
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static struct ctl_table abi_table2[] = {
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{
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.procname = "vsyscall32",
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.data = &vdso32_enabled,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec
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},
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{}
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};
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static struct ctl_table abi_root_table2[] = {
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{
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.procname = "abi",
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.mode = 0555,
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.child = abi_table2
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},
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{}
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};
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static __init int ia32_binfmt_init(void)
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{
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register_sysctl_table(abi_root_table2);
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return 0;
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}
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__initcall(ia32_binfmt_init);
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#endif /* CONFIG_SYSCTL */
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#endif /* CONFIG_X86_64 */
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